first,
Once the buyer make an offer, then the product will automatically disappear temporarily from the list of purchase ..
in some cases buyers making multiple offers different products ... for example, to 2, 3, 4 products and so on ....
- Where buyers can see the list of products that already was bidding??
second,
In trading activities would not only one vendor selling the product "X", there will be a lot of sellers who sell similar products ..
ie Person A sells its products this morning, then the product will be on top of the purchase list .. but when the afternoon could have been the product A will be on the bottom of the list in that category because many sellers who sell goods ..
- How can make the A product could be back in the top of the list or on the first page of the purchase list .. because it makes the same products to the list are not good.,,
- in my opinion, give the A feature that can update the product to get back on top, for example up to 5 update.
sorry, my english bad.

thank you ..